Tube-heater



FIG. 1 is a front view of my tube-heater design;

FIG. 2 is a back view of my tube-heater design;

FIG. 3 is a right-side view of my tube-heater design;

FIG. 4 is a left-side view of my tube-heater design;

FIG. 5 is a top view of my tube-heater design;

FIG. 6 is a bottom view of my tube-heater design; and,

FIG. 7 is a perspective view of my tube-heater design. 

The ornamental design for a tube-heater, substantially as shown and described. 